This invention is directed to sanitary napkins, and particularly to sanitary napkins having flaps. More particularly, this invention is directed to an efficient method of securing these flaps that enhances convenience in both manufacturing and in use to the wearer.
Sanitary napkins having flaps extending outwardly from the longitudinal side margins are well known in the art. For example, U.S. Pat. No. 4,589,876 issued May 20, 1986, to Van Tilburg and U.S. Pat No. 4,687,478 issued Aug. 18, 1987, to Van Tilburg disclose preferred sanitary napkins with flaps and are incorporated herein by reference to illustrate flapped sanitary napkin constructions.
It is also well known in the art to fold the flaps to overlay the main body of the pad during the manufacturing process. For example, U.S. Pat. No. 4,759,754 to Korpman an adhesive tab is used for maintaining the flaps in the desired disposition overlaying the backsheet during packaging. U.S. Pat. No. 4,701,178 issued Oct. 20, 1987, to Glaug et al. discloses a sanitary napkin having a single release strip which covers the centrally located adhesive of the backsheet and over which release strip the flaps are folded.
Alternative means for maintaining the flaps in a folded disposition prior to first use of the sanitary napkin by the wearer are shown for example, in U.S. Pat. No. 4,285,343 to McNair which discloses a sanitary napkin with flaps (side panels) that are folded over the upper surface of the central absorbent element for packaging and at the time of the first use by the wearer, the flaps are usually unfolded to facilitate installation of the sanitary napkin into the wearer""s undergarment. Adhesive patches on a garment facing surface of the flaps are covered with individual strips of release paper. An alternative method of holding the flaps in place is to utilize the release strip paper present on the attachment adhesive located on the flaps. EP 0 347 319 B1 to Marsot and WO 88/04546 to Ternstrom disclose the use of a single release paper in the form of a bridging strip across the flap adhesive patches for maintaining the flaps in the folded disposition prior to the wearer""s first use of the sanitary napkin. Two additional examples of this technique are shown in U.S. Pat. No. 5,800,654, to Davis et al. and U.S. Pat. No. 5,662,639 to Tanaka et al. In these methods the attachment adhesive on the flaps is applied in a conventional manner, i.e. via a transfer coating method and a single sheet of release paper acts both as a protective peel strip for the adhesively coated flaps and as a means to hold the flaps in their folded position.
Use of this method has several drawbacks. In particular, it requires that the flaps be maintained in a parallel position relative to one another. If one or both flaps becomes skewed during manufacture, the adhesive will not be correctly placed on one or both of the flaps, thus rendering it useless. One method of overcoming this problem is to make the peel strip quite large to accommodate this potential skewing.
Accordingly, it is an object of this invention to overcome certain problems of the prior art. Particularly, it is an object of this invention to provide a means to conveniently maintain the flaps in their manufactured, folded position and to do so as to minimize the effects of any skewing problems. Further, this method would accommodate designs in which asymmetrical flaps or uniquely sized releasable strips are employed, without using an excessively large amount of release paper.
In accordance with the present invention, there has been provided a novel a sanitary napkin comprising a liquid-permeable topsheet, a liquid-impermeable backsheet bonded to said topsheet, a liquid-absorbent core disposed between said topsheet and said backsheet, said napkin having transversely opposite side edges and first and second flaps each having upper and lower surfaces and extending outward from said transversely opposite side edges of said napkin and folded back onto said topsheet above said core respectively, wherein: each flap having a layer of adhesive on at least a portion of the lower surface of each said flap and a release strip covering each said layer of adhesive, each said release strip having a first and second surface, each said first surface having a release coating thereon and being in facing relationship with said adhesive layer and thereby creating an adhesive bond between said first surface and said flap; each said second surface having a layer of cohesive material on at least a portion thereof; and, a bridging strip having an outer and an inner surface, said inner surface being in a facing relationship with the second surface of each of said release strips, said inner surface having a layer of cohesive material on at least a portion thereof such that each said layer of cohesive material creates a cohesive bond between said bridging strip and each of said release strips.
Also provided in accordance with the present invention is a novel sanitary napkin comprising a liquid-permeable topsheet, a liquid-impermeable backsheet bonded to said topsheet, a liquid-absorbent core disposed between said topsheet and said backsheet, said napkin having transversely opposite side edges and first and second flaps each having upper and lower surfaces and extending outward from said transversely opposite side edges of said napkin and folded back onto said topsheet above said core respectively, wherein: each flap having a layer of adhesive on at least a portion of the lower surface of each said flap and a release strip covering each said layer of adhesive, each said release strip having a first and second surface, each said first surface having a release coating thereon and being in facing relationship with said adhesive layer and thereby creating an adhesive bond between said first surface and said flap; each said second surface having a layer of cohesive material on at least a portion thereof; and, a bridging strip having an outer and an inner surface, said inner surface being in a facing relationship with the second surface of each of said release strips; said bridging strip further having first and second end portions, the first end portion being folded back onto the inner surface of said bridging strip; each end portion that is in a facing position with the second surface of each of said release strips, having a layer of cohesive material on at least a portion thereof, such that each said layer of cohesive material creates a cohesive bond between said bridging strip and each of said release strips.
Still further provided in accordance with the present invention is a novel sanitary napkin comprising a liquid-permeable topsheet, a liquid-impermeable backsheet bonded to said topsheet, a liquid-absorbent core disposed between said topsheet and said backsheet, said napkin having a two transversely opposite side edges and two transversely opposite end edges, said napkin having a first pair of flaps located in a region of the napkin substantially equidistant between said end edges, said first pair of flaps adapted to be folded over a crotch portion of an undergarment; said napkin having a second pair of flaps located in a region of the napkin substantially adjacent to one of said two transversely opposite end edges, wherein: each flap of said first and second pair of flaps having an upper and a lower surface and each flap extending outward from said transversely opposite side edges of said napkin and folded back onto said topsheet above said core respectively, each flap having a layer of adhesive on at least a portion of the lower surface of each said flap and a release strip covering each said layer of adhesive, each said release strip having a first and second surface, each said first surface having a release coating thereon and being in facing relationship with said adhesive layer and thereby creating an adhesive bond between said first surface and said flap; each said second surface having a layer of cohesive material on at least a portion thereof; and, a bridging strip comprising an outer and an inner surface, said inner surface being in a facing relationship with the second surface of each of said release strips, said inner surface having a layer of cohesive material on at least a portion thereof such that each said layer of cohesive material creates a cohesive bond between said bridging strip and each of said release strips.
Still further provided with the present invention is a novel sanitary napkin comprising a liquid-permeable topsheet, a liquid-impermeable backsheet bonded to said topsheet, a liquid-absorbent core disposed between said topsheet and said backsheet, said napkin having a two transversely opposite side edges and two transversely opposite end edges, said napkin having a first pair of flaps located in a region of the napkin substantially equidistant between said end edges, said first pair of flaps adapted to be folded over a crotch portion of an undergarment; said napkin having a second pair of flaps located in a region of the napkin substantially adjacent to one of said two transversely opposite end edges, wherein: each flap of said first and second pair of flaps having an upper and a lower surface and each flap extending outward from said transversely opposite side edges of said napkin and folded back onto said topsheet above said core respectively, each flap having a layer of adhesive on at least a portion of the lower surface of each said flap and a release strip covering each said layer of adhesive, each said release strip having a first and second surface, each said first surface having a release coating thereon and being in facing relationship with said adhesive layer and thereby creating an adhesive bond between said first surface and said flap; each said second surface having a layer of cohesive material on at least a portion thereof; and, a first and second bridging strip, wherein each of said bridging strips comprise an outer and an inner surface, said inner surface being in a facing relationship with the second surface of each of said release strips, wherein said inner surface of the first bridging strip comprises a layer of cohesive material on at least a portion thereof thereby creating a cohesive bond between said first bridging strip and each of said release strips of said first pair of flaps, and wherein said inner surface of the second bridging strip comprises a layer of cohesive material on at least a portion thereof thereby creating a cohesive bond between said second bridging strip and each of said release strips of said second pair of flaps.
Still further provided with the present invention is a novel process for manufacturing sanitary napkins in which cohesive is used to join a bridging strip to a sanitary napkin having a liquid pervious topsheet, a liquid impervious backsheet at least partially peripherally joined to said topsheet, an absorbent core intermediate said topsheet and said backsheet, two transversely opposite side edges, and one or more flaps extending outwardly from each transversely opposite side edge, each of said flaps having a face generally coextensive of said topsheet and a face generally coextensive of said backsheet, said process comprising the steps of providing said sanitary napkin in a generally flat position; applying to a section of the face of each said flap coextensive of said backsheet generally contemporaneously an adhesive and a release strip with said adhesive in contacting relationship with said faces, said release strip comprising a side facing said adhesive and a side opposite said adhesive; folding each of said flaps about a line parallel to said transversely opposite side edge so that at least a portion of each of said flap faces that is generally coextensive of said topsheet contacts at least a portion of said topsheet that directly overlies said core, said folding pattern exposing each of said flap faces that is generally coextensive of said backsheet; applying to the side of each release strip opposite said adhesive a cohesive material; providing a bridging strip material having top and bottom surfaces, the bottom surface having a layer of said cohesive material on at least a portion thereof; cutting said bridging strip material to a predetermined length; and, placing said bridging strip material over each release strip thereby creating a cohesive bond between said bridging strip material and each said release strip.